Synthesis of Chabazite-Containing Molecular Sieves and Their Use in the Conversion of Oxygenates to Olefins

ABSTRACT

In a method of synthesizing a silicoaluminophosphate molecular sieve having 90%+CHA framework type character, a reaction mixture is prepared comprising first combining a reactive source of aluminum with a reactive source of phosphorus to form a primary mixture that is aged. A reactive source of silicon and a template for directing the formation of the molecular sieve can then be added to form a synthesis mixture. Crystallization is then induced in the synthesis mixture. Advantageously, (i) the source of silicon comprises an organosilicate, (ii) the source of phosphorus optionally comprises an organophosphate, and (iii) the crystallized silicoaluminophosphate molecular sieve has a crystal size distribution such that its average crystal size is not greater than 5 μm. The molecular sieve can then preferably be used in a hydrocarbon (oxygenates-to-olefins) conversion process.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to, and claims priority to, U.S. Ser.No. 61/083,775, U.S. Ser. No. 61/083,765, U.S. Ser. No. 61/083,760, andU.S. Ser. No. 61/083,749, each filed on Jul. 25, 2008 and entitled,“Synthesis of Chabazite-Containing Molecular Sieves and Their Use in theConversion of Oxygenates to Olefins,” the entire disclosures of each ofwhich are hereby incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates to the synthesis of chabazite-type containingmolecular sieves and their use in the conversion of oxygenates,particularly methanol, to olefins, particularly ethylene and/orpropylene.

BACKGROUND OF THE INVENTION

The conversion of oxygenates to olefins (OTO) is currently the subjectof intense research because it has the potential for replacing thelong-standing steam cracking technology that is today theindustry-standard for producing world scale quantities of ethylene andpropylene. The very large volumes involved suggest that substantialeconomic incentives exist for alternate technologies that can deliverhigh throughputs of light olefins in a cost efficient manner. Whereassteam cracking relies on non-selective thermal reactions of naphtharange hydrocarbons at very high temperatures, OTO exploits catalytic andmicro-architectural properties of acidic molecular sieves under mildertemperature conditions to produce high yields of ethylene and propylenefrom methanol.

Current understanding of the OTO reactions suggests a complex sequencein which three major steps can be identified: (1) an induction periodleading to the formation of an active carbon pool (alkyl-aromatics), (2)alkylation-dealkylation reactions of these active intermediates leadingto products, and (3) a gradual build-up of condensed ring aromatics. OTOis therefore an inherently transient chemical transformation in whichthe catalyst is in a continuous state of change. The ability of thecatalyst to maintain high olefin yields for prolonged periods of timerelies on a delicate balance between the relative rates at which theabove processes take place. The formation of coke-like molecules is ofsingular importance because their accumulation interferes with thedesired reaction sequence in a number of ways. In particular, cokerenders the carbon pool inactive, lowers the rates of diffusion ofreactants and products, increases the potential for undesired secondaryreactions and limits catalyst life.

Over the last two decades, many catalytic materials have been identifiedas being useful for carrying out the OTO reactions. Crystallinemolecular sieves are the preferred catalysts today because theysimultaneously address the acidity and morphological requirements forthe reactions. Particularly preferred materials are eight-membered ringaluminosilicates, such as those having the chabazite (CHA) frameworktype, as well as aluminophosphates (AlPOs) and silicoaluminophosphates(SAPOs) of the CHA framework type, such as SAPO-34.

Chabazite is a naturally occurring zeolite with the approximate formulaCa₆Al₁₂Si₂₄O₇₂. Three synthetic forms of chabazite are described in“Zeolite Molecular Sieves”, by D. W. Breck, published in 1973 by JohnWiley & Sons, the complete disclosure of which is incorporated herein byspecific reference. The three synthetic forms reported by Breck areZeolite “K-G”, described in J. Chem. Soc., p. 2822 (1956), Barrer et al;Zeolite D, described in British Patent No. 868,846 (1961); and ZeoliteR, described in U.S. Pat. No. 3,030,181 (1962). Zeolite K-G zeolite hasa silica:alumina mole ratio of 2.3:1 to 4.15:1, whereas zeolites D and Rhave silica:alumina mole ratios of 4.5:1 to 4.9:1 and 3.45:1 to 3.65:1,respectively.

In U.S. Pat. No. 4,440,871, the synthesis of a wide variety of SAPOmaterials of various framework types is described with a number ofspecific examples. Also disclosed are a large number of possible organictemplates, with some specific examples. In the specific examples anumber of CHA framework type materials are described. The preparation ofSAPO-34 is reported, using tetraethylammonium hydroxide (TEAOH), orisopropylamine, or mixtures of TEAOH and dipropylamine (DPA) astemplates. Also disclosed is a specific example that utilizescyclohexylamine in the preparation of SAPO-44. Although other templatematerials are described, there are no other templates indicated as beingsuitable for preparing SAPO's of the CHA framework type.

U.S. Pat. No. 6,162,415 discloses the synthesis of asilicoaluminophosphate molecular sieve, SAPO-44, which has a CHAframework type in the presence of a directing agent comprisingcyclohexylamine or a cyclohexylammonium salt, such as cyclohexylammoniumchloride or cyclohexylammonium bromide.

Silicoaluminophosphates of the CHA framework type with low siliconcontents are particularly desirable for use in the methanol-to-olefinsprocess. Thus, Wilson, et al., Microporous and Mesoporous Materials, 29,117-126, 1999 report that it is beneficial to have lower Si content formethanol-to-olefins reaction, in particular because low Si content hasthe effect of reducing propane formation and decreasing catalystdeactivation.

U.S. Pat. No. 6,620,983 discloses a method for preparingsilicoaluminophosphate molecular sieves, and in particular low silicasilicoaluminophosphate molecular sieve having a Si/Al atomic ratio ofless than 0.5, which process comprises forming a reaction mixturecomprising a source of aluminum, a source of silicon, a source ofphosphorus, at least one organic template, at least one compound whichcomprises two or more fluorine substituents and capable of providingfluoride ions, and inducing crystallization of thesilicoaluminophosphate molecular sieve from the reaction mixture.Suitable organic templates are said to include one or more of tetraethylammonium hydroxide, tetraethyl ammonium phosphate, tetraethyl ammoniumfluoride, tetraethyl ammonium bromide, tetraethyl ammonium chloride,tetraethyl ammonium acetate, dipropylamine, isopropylamine,cyclohexylamine, morpholine, methylbutylamine, morpholine,diethanolamine, and triethylamine In the Examples, crystallization isconducted by heating the reaction mixture to 170° C. over 18 hours andthen holding the mixture at this temperature for 18 hours to 4 days.

U.S. Pat. No. 6,793,901 discloses a method for preparing a microporoussilicoaluminophosphate molecular sieve having the CHA framework type,which process comprises (a) forming a reaction mixture comprising asource of aluminum, a source of silicon, a source of phosphorus,optionally at least one source of fluoride ions and at least onetemplate containing one or more N,N-dimethylamino moieties, (b) inducingcrystallization of the silicoaluminophosphate molecular sieve from thereaction mixture, and (c) recovering silicoaluminophosphate molecularsieve from the reaction mixture. Suitable templates are said to includeone or more of N,N-dimethylethanolamine, N,N-dimethylbutanolamine,N,N-dimethylheptanolamine, N,N-dimethylhexanolamine,N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine,N,N-dimethylbutylene-diamine, N,N-dimethylheptylenediamine,N,N-dimethylhexylenediamine, or dimethyl-ethylamine,dimethylpropylamine, dimethyl-heptylamine, and dimethylhexylamine. Whenconducted in the presence of fluoride ions, the synthesis is effectivein producing low silica silicoaluminophosphate molecular sieves having aSi/Al atomic ratio of from 0.01 to 0.1. In the Examples, crystallizationis conducted by heating the reaction mixture to 170 to 180° C. for 1 to5 days.

U.S. Pat. No. 6,835,363 discloses a process for preparing microporouscrystalline silicoaluminophosphate molecular sieves of CHA frameworktype, the process comprising: (a) providing a reaction mixturecomprising a source of alumina, a source of phosphate, a source ofsilica, hydrogen fluoride and an organic template comprising one or morecompounds of formula (I):

(CH₃)₂N—R—N(CH₃)₂

where R is an alkyl radical of from 1 to 12 carbon atoms; (b) inducingcrystallization of silicoaluminophosphate from the reaction mixture; and(c) recovering silicoaluminophosphate molecular sieve. Suitabletemplates are said to include one or more of the group consisting of:N,N,N′,N′-tetramethyl-1,3-propane-diamine,N,N,N′,N′-tetramethyl-1,4-butanediamine, N,N,N′,N′-tetramethyl-1,3-butanediamine, N,N,N′,N′-tetramethyl-1,5-pentanediamine,N,N,N′,N′-tetramethyl-1,6-hexanediamine,N,N,N′,N′-tetramethyl-1,7-heptanediamine,N,N,N′,N′-tetramethyl-1,8-octanediamine,N,N,N′,N′-tetramethyl-1,9-nonanediamineN,N,N′,N′-tetramethyl-1,10-decanediamine,N,N,N′,N′-tetramethyl-1,11-undecanediamine andN,N,N′,N′-tetramethyl-1,12-dodecanediamine. In the Examples,crystallization is conducted by heating the reaction mixture to 120 to200° C. for 4 to 48 hours.

U.S. Pat. No. 7,247,287 discloses the synthesis ofsilicoaluminophosphate molecular sieves having the CHA framework typeemploying a directing agent having the formula:

R¹R²N—R³

wherein R¹ and R² are independently selected from the group consistingof alkyl groups having from 1 to 3 carbon atoms and hydroxyalkyl groupshaving from 1 to 3 carbon atoms and R³ is selected from the groupconsisting of 4- to 8-membered cycloalkyl groups, optionally substitutedby 1 to 3 alkyl groups having from 1 to 3 carbon atoms; and 4- to8-membered heterocyclic groups having from 1 to 3 heteroatoms, saidheterocyclic groups being optionally substituted by 1 to 3 alkyl groupshaving from 1 to 3 carbon atoms and the heteroatoms in said heterocyclicgroups being selected from the group consisting of O, N, and S.Preferably, the directing agent is selected fromN,N-dimethylcyclohexylamine, N,N-dimethyl-methylcyclohexylamine,N,N-dimethyl-cyclopentylamine, N,N-dimethyl-methylcyclopentylamine,N,N-dimethylcycloheptyl-amine, N,N-dimethyl-methyl-cycloheptylamine, andmost preferably is N,N-dimethyl-cyclohexylamine. The synthesis can beeffected with or without the presence of fluoride ions and, in theExamples, crystallization is conducted by heating the reaction mixtureto 180° C. for 3 to 7 days.

According to the present invention, it has unexpectedly been found thatthe order of addition and relative homogenization of the synthesismixture components, as well as whether certain synthesis mixturecomponents are inorganic or organic, in silicoaluminophosphate molecularsieve formulations can enhance certain desirable properties, such asreducing the crystal size of the product, while still maintaining anacceptable product yield. Interestingly, the use of organic sources ofsilicon, and optionally also phosphorus, as opposed to inorganicsources, can facilitate a more intimate/reactive combination ofsynthesis mixture components and appears to be a robust way to make thesynthesis mixture, preferably resulting in more desirable molecularsieve products.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a method of preparing asilicoaluminophosphate molecular sieve having a desired crystal size,the method comprising: (a) combining a source of phosphorus and a sourceof aluminum, optionally with a liquid mixture medium, to form a primarymixture; (b) aging the primary mixture for an aging time and under agingconditions sufficient to allow homogenization of the primary mixture,physico-chemical interaction between the source of phosphorus and thesource of aluminum, or both; (c) adding a source of silicon, at leastone organic template, and optionally additional liquid mixture medium,to the aged primary mixture to form a synthesis mixture; and (d)inducing crystallization of a silicoaluminophosphate molecular sieve,which exhibits 90% or greater CHA framework type character, from saidsynthesis mixture at a crystallization temperature, wherein said sourceof silicon comprises an organosilicate and said source of phosphorusoptionally comprises an organophosphate, and wherein the crystallizedsilicoaluminophosphate molecular sieve has a crystal size distributionsuch that its average crystal size is not greater than 5 μm.

In another aspect, the invention relates to a method of convertinghydrocarbons into olefins comprising: (a) preparing asilicoaluminophosphate molecular sieve according to the method of theprevious aspect of the invention; (b) formulating saidsilicoaluminophosphate molecular sieve, along with a binder andoptionally a matrix material, into a silicoaluminophosphate molecularsieve catalyst composition comprising from at least 10% to about 50%molecular sieve; and (c) contacting said catalyst composition with ahydrocarbon feed under conditions sufficient to convert said hydrocarbonfeed into a product comprising predominantly one or more olefins.

In another aspect, the invention relates to a method of forming anolefin-based polymer product comprising: (a) preparing asilicoaluminophosphate molecular sieve according to the method of thefirst aspect of the invention; (b) formulating saidsilicoaluminophosphate molecular sieve, along with a binder andoptionally a matrix material, into a silicoaluminophosphate molecularsieve catalyst composition comprising from at least 10% to about 50%molecular sieve; (c) contacting said catalyst composition with ahydrocarbon feed under conditions sufficient to convert said hydrocarbonfeed into a product comprising predominantly one or more olefins; (d)polymerizing at least one of the one or more olefins, optionally withone or more other comonomers and optionally in the presence of apolymerization catalyst, under conditions sufficient to form anolefin-based (co)polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an X-ray diffraction (XRD) analysis of a molecular sievemade according to Comparative Example A1.

FIG. 2 shows an SEM micrograph of a molecular sieve made according toComparative Example A1.

FIG. 3 shows an XRD analysis of a molecular sieve made according toComparative Example A2.

FIG. 4 shows an SEM micrograph of a molecular sieve made according toComparative Example A2.

FIG. 5 shows an XRD analysis of a molecular sieve made according toExample 1.

FIG. 6 shows an SEM micrograph of a molecular sieve made according toExample 1.

FIG. 7 shows an XRD analysis of a molecular sieve made according toExample 2.

FIG. 8 shows an SEM micrograph of a molecular sieve made according toExample 2.

FIG. 9 shows an SEM micrograph of a molecular sieve made according toExample 3.

FIG. 10 shows an SEM micrograph of a molecular sieve made according toExample 4.

FIG. 11 shows an SEM micrograph of a molecular sieve made according toComparative Example B 1.

FIG. 12 shows an SEM micrograph of a molecular sieve made according toExample 5.

FIG. 13 shows an SEM micrograph of a molecular sieve made according toExample 6.

FIG. 14 shows an SEM micrograph of a molecular sieve made according toExample 14.

FIG. 15 shows a graph of the yield of products made according to theinvention with different silica sources and having various Si/Al₂ ratiosin the synthesis mixture.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Described herein is a method of synthesizing a crystallinealuminophosphate or silicoaluminophosphate containing a molecular sievehaving 90% or greater CHA framework-type character and to the use of theresultant molecular sieve as a catalyst in organic conversion reactions,especially the conversion of oxygenates to light olefins.

In particular, it has been found that, by employing a particular orderof addition of components (i.e., phosphorus and aluminum sources beingcombined first) and by incorporating certain organic sources (e.g.,organosilicate and optionally also organophosphate) in the molecularsieve synthesis, it is possible to produce a 90% or greater CHAframework-type containing molecular sieve having a desirably reducedcrystal size, e.g., 5 microns or less, instead of over 10 microns.

In a preferred embodiment, the order of addition of the components inthe mixture (i.e., in step (a)) can be important and can advantageouslybe tailored, e.g., to provide better homogeneity. For instance, step (a)can preferably comprise: (i) combining the source of phosphorus and thesource of aluminum, optionally with a liquid mixture medium, to form aprimary mixture; (ii) aging the primary mixture for an aging time andunder aging conditions (e.g., at an aging temperature), preferablysufficient to allow homogenization of the primary mixture,physico-chemical interaction between the source of phosphorus and thesource of aluminum, or both; and (iii) adding the source of silicon, theat least one organic template, and optionally additional liquid mixturemedium, to the aged primary mixture to form the synthesis mixture. Incertain cases of this embodiment, within step (iii), said source ofsilicon is combined with said primary mixture prior to adding said atleast one organic template (structure directing agent, or SDA).Advantageously, said primary mixture and said source of silicon can becombined to form a secondary mixture for a time and under conditions(e.g., temperature), preferably sufficient to allow homogenization ofthe secondary mixture, physico-chemical interaction between said sourceof silicon and said primary mixture, or both, after which said at leastone organic template is combined therewith.

When a component is added to a mixture to allow homogenization and/orphysico-chemical interaction, the aging time and temperature are two ofthe primary conditions. Although a variety of conditions can exist toallow sufficient contact for homogenization and/or interaction, in oneembodiment, when the aging temperature is somewhere between 0° C. and50° C., the aging time can advantageously be at least 5 minutes, forexample at least 10 minutes, at least 15 minutes, at least 20 minutes,at least 25 minutes, at least 30 minutes, at least 45 minutes, at least1 hour, or at least 2 hours. Again, when the aging temperature issomewhere between 0° C. and 50° C., the aging time does not really havea maximum, but can be up to 350 hours, for example up to 300 hours, upto 250 hours, up to 200 hours, up to 168 hours, up to 96 hours, up to 48hours, up to 24 hours, up to 16 hours, up to 12 hours, up to 8 hours, upto 6 hours, or up to 4 hours, depending on practical concerns relatingto synthesis timing, cost efficiency, manufacture schedules, or thelike.

In the present method, a reaction mixture is prepared comprising asource of aluminum, a source of phosphorous, at least one organicdirecting agent, and, optionally, a source of silicon. Any organicdirecting agent capable of directing the synthesis of CHA framework typemolecular sieves can be employed, but generally the directing agent is acompound having the formula (I):

R¹R²N—R³   (I)

wherein R¹ and R² are independently selected from the group consistingof alkyl groups having from 1 to 3 carbon atoms and hydroxyalkyl groupshaving from 1 to 3 carbon atoms and R³ is selected from the groupconsisting of 4- to 8-membered cycloalkyl groups, optionally substitutedby 1 to 3 alkyl groups having from 1 to 3 carbon atoms; and 4- to8-membered heterocyclic groups having from 1 to 3 heteroatoms, saidheterocyclic groups being optionally substituted by 1 to 3 alkyl groupshaving from 1 to 3 carbon atoms and the heteroatoms in said heterocyclicgroups being selected from the group consisting of O, N, and S.

More particularly, the organic directing agent is a compound having theformula (II):

(CH₃)₂N—R³   (II)

wherein R³ is a 4- to 8-membered cycloalkyl group, especially acyclohexyl group, optionally substituted by 1 to 3 methyl groups.Particular examples of suitable organic directing agents include, butare not limited to, at least one of N,N-dimethyl-cyclohexylamine,N,N-dimethyl-methylcyclohexylamine, N,N-dimethyl-cyclopentylamine,N,N-dimethyl-methylcyclopentylamine, N,N-dimethyl-cycloheptylamine, andN,N-dimethyl-methylcycloheptylamine, especiallyN,N-dimethyl-cyclohexylamine

The sources of aluminum, phosphorus, and silicon suitable for use in thepresent synthesis method are typically those known in the art or asdescribed in the literature for the production of aluminophosphates andsilicoaluminophosphates. For example, the aluminum source may be analuminum oxide (alumina), optionally hydrated, an aluminum salt,especially a phosphate, an aluminate, or a mixture thereof Other sourcesmay include alumina sols or organic alumina sources, e.g., aluminumalkoxides such as aluminum isopropoxide. A preferred source is ahydrated alumina, most preferably pseudoboehmite, which contains about75% Al₂O₃ and 25% H₂O by weight. Typically, the source of phosphorus isa phosphoric acid, especially orthophosphoric acid, although otherphosphorus sources, for example, organophosphates (e.g.,trialkylphosphates such as triethylphosphate) and aluminophosphates maybe used. When organophosphates and/or aluminophosphates are used,typically they are present collectively in a minor amount (i.e., lessthan 50% by weight of the phosphorus source) in combination with amajority (i.e., at least 50% by weight of the phosphorus source) of aninorganic phosphorus source (such as phosphoric acid). Suitable sourcesof silicon include silica, for example colloidal silica and fumedsilica, as well as organic silicon source, e.g., a tetraalkylorthosilicate, preferably such as tetraethylorthosilicate (TEOS),tetramethylorthosilicate (TMOS), or the like, or a combination thereof.

Although, in most embodiments, the sources of silicon, phosphorus, andaluminum are the only components that form the framework of a calcinedsilicoaluminophosphate molecular sieve according to the invention, it ispossible for some small portion (e.g., typically no more than about 10wt %, preferably no more than about 5 wt %) of the silicon source can besubstituted with a source of one or more of magnesium, zinc, iron,cobalt, nickel, manganese, and chromium.

In some embodiments, the reaction mixture can have a molar compositionwithin the following ranges:

-   -   P₂O₅:Al₂O₃ from about 0.75 to about 1.25,    -   SiO₂:Al₂O₃ from about 0.01 to about 0.32,    -   H₂O:Al₂O₃ from about 25 to about 50, and    -   SDA:Al₂O₃ from about 1 to about 3,        where SDA designates the structure directing agent (template),        and wherein the molar ratios for the aluminum, phosphorus, and        silicon sources are calculated based on the oxide forms,        regardless of the form of the source added to the reaction        mixture (e.g., whether the phosphorus source is added to the        reaction mixture as phosphoric acid, H₃PO₄, or as        triethylphosphate, the molar ratio is normalized to P₂O₅ molar        equivalents).

Although the reaction mixture may also contain a source of fluorideions, it is found that the present synthesis will proceed in the absenceof fluoride ions, and hence it is generally preferred to employ areaction mixture which is substantially free of fluoride ions.

Typically, the reaction mixture also contains seeds to facilitate thecrystallization process. The amount of seeds employed can vary widely,but generally the reaction mixture comprises from about 0.01 ppm byweight to about 10,000 ppm by weight, such as from about 100 ppm byweight to about 5,000 by weight, of said seeds. Generally, the seeds canbe homostructural with the desired product, that is are of a CHAframework type material, although heterostructural seeds of, forexample, an AEI, LEV, ERI, AFX, or OFF framework-type molecular sieve,or a combination or intergrowth thereof, may be used. The seeds may beadded to the reaction mixture as a suspension in a liquid medium, suchas water; in some cases, particularly where the seeds are of relativelysmall size, the suspension can be colloidal. The production of colloidalseed suspensions and their use in the synthesis of molecular sieves aredisclosed in, for example, International Publication Nos. WO 00/06493and WO 00/06494, both published on Feb. 10, 2000 and both of which areincorporated herein by reference.

Crystallization of the reaction mixture is carried out at either staticor stirred conditions in a suitable reactor vessel, such as for example,polypropylene jars or Teflon-lined or stainless steel autoclaves. In oneembodiment, the crystallization regime can involve heating the reactionmixture relatively quickly, at a rate of more than 10° C./hour,conveniently at least 15° C./hour or at least 20° C./hour, for examplefrom about 15° C./hour to about 150° C./hour or from about 20° C./hourto about 100° C./hour, to the desired crystallization temperature,typically between about 50° C. and about 250° C., for example from about150° C. to about 225° C. or from about 150° C. to about 200° C., such asfrom about 160° C. to about 195° C. In some embodiments, however, thedesired crystallization temperature is additionally at least 165° C.,for example at least 170° C., and can optionally also be not more than190° C., for example not more than 185° C. or not more than 180° C. Inany of these embodiments, when the desired crystallization temperatureis reached, the crystallization can be terminated immediately or fromabout 5 minutes to about 350 hours, and the reaction mixture can beallowed to cool; additionally or alternately, the crystallization canrun for at least about 12 hours, preferably at least about 16 hours, forexample at least 24 hours, at least 36 hours, at least 48 hours, atleast 60 hours, at least 72 hours, at least 84 hours, at least 96 hours,at least 120 hours, or at least 144 hours before cooling. Additionallyin this embodiment, on cooling, the crystalline product can be recoveredby standard means, such as by centrifugation or filtration, then washedand dried.

In an alternate embodiment, the crystallization regime can involveheating the reaction mixture slowly, at a rate of less than 8° C./hour,conveniently at least 1° C./hour, such as from about 2° C./hour to about6° C./hour, to the desired crystallization temperature, typicallybetween about 50° C. and about 250° C., for example from about 150° C.to about 225° C. or from about 150° C. to about 200° C., such as fromabout 160° C. to about 195° C. In some embodiments, however, the desiredcrystallization temperature is additionally at least 165° C., forexample at least 170° C., and can optionally also be not more than 190°C., for example not more than 185° C. or not more than 180° C. In any ofthese embodiments, when the desired crystallization temperature isreached, the crystallization can be terminated immediately or at leastwithin less than 10 hours, such as less than 5 hours, and the reactionmixture can be allowed to cool. Additionally in this embodiment, oncooling, the crystalline product can be recovered by standard means,such as by centrifugation or filtration, then washed and dried.

Optionally, the step of inducing crystallization can be done whilestirring.

In one embodiment, the crystallized silicoaluminophosphate molecularsieve has a crystal size distribution such that its average crystal sizeis no more than 5 μm, preferably no more than 3.0 μm, for example nomore than 2.0 μm, no more than 1.5 μm, no more than 1.2 μm, no more than1.1 μm, no more than 1.0 μm, or no more than 0.9 μm.

As used herein, the term “average crystal size,” in reference to acrystal size distribution, should be understood to refer to ameasurement on a representative sample or an average of multiple samplesthat together form a representative sample. Average crystal size can bemeasured by SEM, in which case the crystal size of at least 30 crystalsmust be measured in order to obtain an average crystal size, and/oraverage crystal size can be measured by a laser light scatteringparticle size analyzer instrument, in which case the measured d₅₀ of thesample(s) can represent the average crystal size. It should also beunderstood that, while many of the crystals dealt with herein arerelatively uniform (for instance, very close to cubic, thus havinglittle difference between diameter measured along length, height, orwidth, e.g., when viewed in an SEM), the “average crystal size,” whenmeasured visually by SEM, represents the longest distance along one ofthe three-dimensional orthogonal axes (e.g., longest of length,width/diameter, and height, but not diagonal, in a cube, rectangle,parallelogram, ellipse, cylinder, frusto-cone, platelet, spheroid, orrhombus, or the like). However, the d₅₀, when measured by lightscattering in a particle size analyzer, is reported as a sphericalequivalent diameter, regardless of the shape and/or relative uniformityof shape of the crystals in each sample. In certain circumstances, thed₅₀ values measured by the particle size analyzer may not correspond,even roughly, to the average crystal size measured visually by arepresentative SEM micrograph. Often in these cases, the discrepancyrelates to an agglomeration of relatively small crystals that theparticle size analyzer interprets as a single particle. In suchcircumstances, where the d₅₀ values from the particle size analyzer andthe average crystal size from a representative SEM are significantlydifferent, the representative SEM micrograph should be the more accuratemeasure of “average crystal size.”

Preferably, the Si/Al₂ ratio added to the synthesis mixture can be asclose as possible to the Si/Al₂ ratio of the crystallizedsilicoaluminophosphate molecular sieve (e.g., difference between theSi/Al₂ ratio in the synthesis mixture and in the crystallizedsilicoaluminophosphate molecular sieve can be no more than 0.10,preferably no more than 0.08, for example no more than 0.07) and/or thesynthesis mixture and the crystallized silicoaluminophosphate molecularsieve can both exhibit a relatively low Si/Al₂ ratio (e.g., both can beless than 0.33, preferably less than 0.30, for example no more than0.25, no more than 0.20, no more than 0.15, or no more than 0.10).

In a preferred embodiment, one or more of the following are satisfied:the source of aluminum comprises alumina; the source of phosphoruscomprises phosphoric acid and an organophosphate comprising atrialkylphosphate; the source of silicon can include an organosilicatecomprising a tetraalkylorthosilicate; and the at least one organictemplate comprises N,N-dimethylcyclohexylamine.

The product of the crystallization is an aluminophosphate orsilicoaluminophosphate containing a CHA framework-type molecular sievehaving an X-ray diffraction pattern including at least the d-spacingsshown in Table 1 below:

TABLE 1 Relative Intensities d(A) I/Io (%) 9.26 100 6.30 20 5.64 15 5.5157 4.96 25 4.92 27 4.29 76 4.18 21 3.55 32 3.50 20 3.42 10 2.91 22 2.8826 2.87 19

Although the crystallization product is normally a single phase CHAframework-type molecular sieve, in some cases the product may contain anintergrowth of a CHA framework-type molecular sieve with, for example anAEI framework-type molecular sieve or small amounts of other crystallinephases, such as APC and/or AFI framework-type molecular sieves. In oneembodiment, it is preferable for the crystallization product to have ashigh an amount of CHA framework type as possible, e.g., at least 95% CHAframework-type character, or even about 100% CHA framework-typecharacter (or as close as possible to single phase CHA framework-typecharacter as can currently be measured). Without being bound by theory,it is believed that silicoaluminophosphate molecular sieves havingincreased CHA framework-type character (and/or increased uniformity ofdistribution of silicon within the molecular sieve framework structure,i.e., decreased amounts of silicon islanding) can advantageously exhibitbetter performance (e.g., increased POS, which means prime olefinselectivity, or selectivity to the combination of ethylene andpropylene, and optionally also POR, which means prime olefin, orethylene-to-propylene, ratio) in oxygenates-to-olefins conversionreactions, particularly in methanol-to-olefins conversion reactions.

As a result of the crystallization process, the recovered crystallineproduct contains within its pores at least a portion of the organicdirecting agent used in the synthesis. In a preferred embodiment,activation is performed in such a manner that the organic directingagent is removed from the molecular sieve, leaving active catalyticsites within the microporous channels of the molecular sieve open forcontact with a feedstock. The activation process is typicallyaccomplished by calcining, or essentially heating the molecular sievecomprising the template at a temperature of from about 200° C. to about800° C. in the presence of an oxygen-containing gas. In some cases, itmay be desirable to heat the molecular sieve in an environment having alow or zero oxygen concentration. This type of process can be used forpartial or complete removal of the organic directing agent from theintracrystalline pore system.

Once the crystalline product has been activated, it can be formulatedinto a catalyst composition by combination with other materials, such asbinders and/or matrix materials, which provide additional hardness orcatalytic activity to the finished catalyst.

Materials which can be blended with the present molecular sieve materialinclude a large variety of inert and catalytically active materials.These materials include compositions such as kaolin and other clays,various forms of rare earth metals, other non-zeolite catalystcomponents, zeolite catalyst components, alumina or alumina sol,titania, zirconia, quartz, silica or silica sol, and mixtures thereof.These components are also effective in reducing overall catalyst cost,acting as a thermal sink to assist in heat shielding the catalyst duringregeneration, densifying the catalyst and increasing catalyst strength.When blended with such components, the amount of present CHA-containingcrystalline material contained in the final catalyst product ranges from10 to 90 weight percent of the total catalyst, preferably 20 to 80weight percent of the total catalyst.

The CHA framework type crystalline material produced by the presentprocess can be used to dry gases and liquids; for selective molecularseparation based on size and polar properties; as an ion-exchanger; as achemical carrier; in gas chromatography; and as a catalyst in organicconversion reactions. Examples of suitable catalytic uses of the CHAframework type crystalline material described herein include (a)hydrocracking of heavy petroleum residual feedstocks, cyclic stocks andother hydrocrackate charge stocks, normally in the presence of ahydrogenation component selected from Groups 6 and 8-10 of the PeriodicTable of Elements; (b) dewaxing, including isomerization dewaxing, toselectively remove straight chain paraffins from hydrocarbon feedstockstypically boiling above 177° C., including raffinates and lubricatingoil basestocks; (c) catalytic cracking of hydrocarbon feedstocks, suchas naphthas, gas oils, and residual oils, normally in the presence of alarge pore cracking catalyst, such as zeolite Y; (d) oligomerization ofstraight and branched chain olefins having from 2-21, preferably 2-5,carbon atoms, to produce medium to heavy olefins which are useful forboth fuels, e.g., gasoline or a gasoline blending stock, and chemicals;(e) isomerization of olefins, particularly olefins having 4-6 carbonatoms, and especially normal butene to produce iso-olefins; (f)upgrading of lower alkanes, such as methane, to higher hydrocarbons,such as ethylene and benzene; (g) disproportionation of alkylaromatichydrocarbons, such as toluene, to produce dialkylaromatic hydrocarbons,such as xylenes; (h) alkylation of aromatic hydrocarbons, such asbenzene, with olefins, such as ethylene and propylene, to producealkylated aromatics, such as ethylbenzene and cumene; (i) isomerizationof dialkylaromatic hydrocarbons, such as xylenes; (j) catalyticreduction of nitrogen oxides; and (k) synthesis of monoalkylamines anddialkylamines.

In particular, the CHA framework type crystalline material produced bythe present process is useful as a catalyst in the conversion ofoxygenates to one or more olefins, particularly ethylene and propylene.As used herein, the term “oxygenates” is defined to include, but is notnecessarily limited to, aliphatic alcohols, ethers, carbonyl compounds(aldehydes, ketones, carboxylic acids, carbonates, and the like), andalso compounds containing hetero-atoms, such as, halides, mercaptans,sulfides, amines, and mixtures thereof The aliphatic moiety willnormally contain from 1-10 carbon atoms, such as from 1-4 carbon atoms.

Representative oxygenates include lower straight chain or branchedaliphatic alcohols, their unsaturated counterparts, and their nitrogen,halogen, and sulfur analogues. Examples of suitable oxygenate compoundscan include, but are not necessarily limited to: methanol; ethanol;n-propanol; isopropanol; C₄ to C₁₀ alcohols; methyl ethyl ether;dimethyl ether; diethyl ether; di-isopropyl ether; methyl mercaptan;methyl sulfide; methyl amine; ethyl mercaptan; di-ethyl sulfide;di-ethyl amine; ethyl chloride; formaldehyde; di-methyl carbonate;di-methyl ketone; acetic acid; n-alkyl amines; n-alkyl halides; n-alkylsulfides having n-alkyl groups comprising from 3-10 carbon atoms; andthe like; and mixtures thereof Particularly suitable oxygenate compoundsare methanol, dimethyl ether, and mixtures thereof, and most preferablycomprise methanol. As used herein, the term “oxygenate” designates onlythe organic material used as the feed. The total charge of feed to thereaction zone may contain additional compounds, such as diluents.

In one embodiment of the oxygenate conversion process, a feedstockcomprising an organic oxygenate, optionally with one or more diluents,is contacted in the vapor phase in a reaction zone with a catalystcomprising the present molecular sieve at effective process conditionsso as to produce the desired olefins. Alternatively, the process may becarried out in a liquid or a mixed vapor/liquid phase. When the processis carried out in the liquid phase or a mixed vapor/liquid phase,different conversion rates and selectivities of feedstock-to-product mayresult depending upon the catalyst and the reaction conditions.

When present, the diluent(s) is(are) generally non-reactive to thefeedstock or molecular sieve catalyst composition and is typically usedto reduce the concentration of the oxygenate in the feedstock.Non-limiting examples of suitable diluents include helium, argon,nitrogen, carbon monoxide, carbon dioxide, water, essentiallynon-reactive paraffins (especially alkanes such as methane, ethane, andpropane), essentially non-reactive aromatic compounds, and mixturesthereof The most preferred diluents include water and nitrogen, withwater being particularly preferred. Diluent(s) may comprise from about 1mol % to about 99 mol % of the total feed mixture.

The temperature employed in the oxygenate conversion process may varyover a wide range, such as from about 200° C. to about 1000° C., forexample from about 250° C. to about 800° C., including from about 250°C. to about 750° C., conveniently from about 300° C. to about 650° C.,typically from about 350° C. to about 600° C. and particularly fromabout 400° C. to about 600° C.

Light olefin products will form, although not necessarily in optimumamounts, at a wide range of pressures, including but not limited toautogenous pressures and pressures in the range from about 0.1 kPa toabout 10 MPa. Conveniently, the pressure can be in the range from about7 kPa to about 5 MPa, such as from about 50 kPa to about 1 MPa. Theforegoing pressures are exclusive of diluents, if any are present, andrefer to the partial pressure of the feedstock as it relates tooxygenate compounds and/or mixtures thereof Lower and upper extremes ofpressure may adversely affect selectivity, conversion, coking rate,and/or reaction rate; however, light olefins such as ethylene and/orpropylene still may form.

In a preferred embodiment, the method of converting hydrocarbons intoolefins according to the invention comprises: (a) preparing asilicoaluminophosphate molecular sieve according to the methodsdisclosed hereinabove; (b) formulating said silicoaluminophosphatemolecular sieve, along with a binder and optionally a matrix material,into a silicoaluminophosphate molecular sieve catalyst composition,typically comprising from at least 10% to about 50% molecular sieve; and(c) contacting said catalyst composition with a hydrocarbon feed underconditions sufficient to convert said hydrocarbon feed into a productcomprising predominantly one or more olefins, preferably to attain aprime olefin selectivity of at least 70 wt % (as measured at about 500°C.). Preferably, the hydrocarbon feed is an oxygenate-containing feedcomprising methanol, dimethylether, or a combination thereof, and theone or more olefins typically comprises ethylene, propylene, or acombination thereof.

A wide range of weight hourly space velocities (WHSV) for the feedstockwill function in the oxygenate conversion process. WHSV is defined asweight of feed (excluding diluents) per hour per weight of a totalreaction volume of molecular sieve catalyst (excluding inert and/orfillers). The WHSV generally should be in the range from about 0.01 hr⁻¹to about 500 hr⁻¹, such from about 0.5 hr⁻¹ to about 300 hr⁻¹, forexample from about 0.1 hr⁻¹ to about 200 hr⁻¹.

A practical embodiment of a reactor system for the oxygenate conversionprocess is a circulating fluid bed reactor with continuous regeneration.Fixed beds are generally not preferred for the process, becauseoxygenate-to-olefin conversion is a highly exothermic process thatrequires several stages with intercoolers or other cooling devices. Thereaction also results in a high pressure drop, due to the production oflow pressure, low density gas.

Because the catalyst typically needs to be regenerated frequently, thereactor should preferably allow easy removal of at least a portion ofthe catalyst to a regenerator, where the catalyst can be subjected to aregeneration medium, such as a gas comprising oxygen, for example air,to burn off coke from the catalyst, which should restore at least someof the catalyst activity. The conditions of temperature, oxygen partialpressure, and residence time in the regenerator can typically beselected to achieve a coke content on regenerated catalyst of less thanabout 1 wt %, for example less than about 0.5 wt %. At least a portionof the regenerated catalyst should be returned to the reactor.

In a preferred embodiment, the method of forming an olefin-based polymerproduct comprises: (a) preparing a silicoaluminophosphate molecularsieve according to the methods described hereinabove; (b) formulatingsaid silicoaluminophosphate molecular sieve, along with a binder andoptionally a matrix material, into a silicoaluminophosphate molecularsieve catalyst composition comprising from at least 10% to about 50%molecular sieve; (c) contacting said catalyst composition with ahydrocarbon feed under conditions sufficient to convert said hydrocarbonfeed into a product comprising predominantly one or more olefins,preferably to attain a prime olefin selectivity of at least 70 wt % (asmeasured at about 500° C.); and (d) polymerizing at least one of the oneor more olefins, optionally with one or more other comonomers andoptionally (but preferably) in the presence of a polymerizationcatalyst, under conditions sufficient to form an olefin-based(co)polymer. Preferably, in this preferred embodiment, the hydrocarbonfeed is an oxygenate-containing feed comprising methanol, dimethylether,or a combination thereof, the one or more olefins typically comprisesethylene, propylene, or a combination thereof, and the olefin-based(co)polymer is an ethylene-containing (co)polymer, apropylene-containing (co)polymer, or a copolymer, mixture, or blendthereof.

Additionally or alternately, the invention can be described by thefollowing embodiments.

Embodiment 1. A method of preparing a silicoaluminophosphate molecularsieve having a desired crystal size, the method comprising: (a)combining a source of phosphorus and a source of aluminum, optionallywith a liquid mixture medium, to form a primary mixture; (b) aging theprimary mixture for an aging time and under aging conditions sufficientto allow homogenization of the primary mixture, physico-chemicalinteraction between the source of phosphorus and the source of aluminum,or both; (c) adding a source of silicon, at least one organic template,and optionally additional liquid mixture medium, to the aged primarymixture to form a synthesis mixture; and (d) inducing crystallization ofa silicoaluminophosphate molecular sieve, which exhibits 90% or greaterCHA framework type character, from said synthesis mixture at acrystallization temperature, wherein said source of silicon comprises anorganosilicate and said source of phosphorus optionally comprises anorganophosphate, and wherein the crystallized silicoaluminophosphatemolecular sieve has a crystal size distribution such that the averagecrystal size is not greater than 5 μm.

Embodiment 2. The method of embodiment 1, wherein the at least oneorganic template contains (i) a 4- to 8-membered cycloalkyl group,optionally substituted by 1-3 alkyl groups having from 1-3 carbon atoms,or (ii) a 4- to 8-membered heterocyclic group having from 1-3heteroatoms, said heterocyclic group being optionally substituted by 1-3alkyl groups having from 1-3 carbon atoms, and said heteroatoms in saidheterocyclic groups being selected from the group consisting of O, N,and S.

Embodiment 3. The method of embodiment 1 or embodiment 2, wherein the atleast one organic template comprises N,N-dimethylcyclohexylamine

Embodiment 4. The method of any of the previous embodiments, wherein thecrystallized silicoaluminophosphate molecular sieve exhibits a Si/Al₂ratio not more than 0.10 greater than the Si/Al₂ ratio of the synthesismixture.

Embodiment 5. The method of any of the previous embodiments, whereinsaid crystallization temperature is between 150° C. and 200° C.

Embodiment 6. The method of any of the previous embodiments, wherein thecrystallized silicoaluminophosphate molecular sieve has a crystal sizedistribution such that the average crystal size is less than 2.0 μm.

Embodiment 7. The method of any of the previous embodiments, wherein thecrystallized silicoaluminophosphate molecular sieve has a crystal sizedistribution such that the average crystal size is less than 1.2 μm.

Embodiment 8. The method of any of the previous embodiments, wherein theinducing step is done while stirring.

Embodiment 9. The method of any of the previous embodiments, wherein,within step (c), said source of silicon is combined with said primarymixture prior to adding said at least one organic template.

Embodiment 10. The method of embodiment 9, wherein said primary mixtureand said source of silicon are combined to form a secondary mixture fora time and under conditions sufficient to allow homogenization of thesecondary mixture, physico-chemical interaction between said source ofsilicon and said primary mixture, or both, after which said at least oneorganic template is combined therewith.

Embodiment 11. The method of any of the previous embodiments, whereinthe synthesis mixture and the crystallized silicoaluminophosphatemolecular sieve both exhibit a Si/Al₂ ratio less than 0.33.

Embodiment 12. The method of any of embodiments 1-2 and 4-11, whereinone or more of the following are satisfied: the source of aluminumcomprises alumina; the source of phosphorus comprises phosphoric acidand an organophosphate comprising a trialkylphosphate; theorganosilicate comprises a tetraalkylorthosilicate; and the at least oneorganic template comprises N,N-dimethylcyclohexylamine

Embodiment 13. The method of any of the previous embodiments, whereinthe organosilicate comprises tetramethylorthosilicate,tetraethylorthosilicate, or a combination thereof.

Embodiment 14. The method of any of the previous embodiments, whereinstep (b) was accomplished using seeds having a framework type of CHA,AEI, AFX, LEV, an intergrowth thereof, or a combination thereof.

Embodiment 15. A method of converting hydrocarbons into olefinscomprising: (a) preparing a silicoaluminophosphate molecular sieveaccording to the method of any of the previous embodiments; (b)formulating said silicoaluminophosphate molecular sieve, along with abinder and optionally a matrix material, into a silicoaluminophosphatemolecular sieve catalyst composition comprising from at least 10% toabout 50% molecular sieve; and (c) contacting said catalyst compositionwith a hydrocarbon feed under conditions sufficient to convert saidhydrocarbon feed into a product comprising predominantly one or moreolefins.

Embodiment 16. The method of embodiment 15, wherein the hydrocarbon feedis an oxygenate-containing feed comprising methanol, dimethylether, or acombination thereof, and wherein the one or more olefins comprisesethylene, propylene, or a combination thereof.

Embodiment 17. A method of forming an olefin-based polymer productcomprising: (a) preparing a silicoaluminophosphate molecular sieveaccording to the method of any of embodiments 1-14; (b) formulating saidsilicoaluminophosphate molecular sieve, along with a binder andoptionally a matrix material, into a silicoaluminophosphate molecularsieve catalyst composition comprising from at least 10% to about 50%molecular sieve; (c) contacting said catalyst composition with ahydrocarbon feed under conditions sufficient to convert said hydrocarbonfeed into a product comprising predominantly one or more olefins; (d)polymerizing at least one of the one or more olefins, optionally withone or more other comonomers and optionally in the presence of apolymerization catalyst, under conditions sufficient to form anolefin-based (co)polymer.

Embodiment 18. The method of embodiment 17, wherein the hydrocarbon feedis an oxygenate-containing feed comprising methanol, dimethylether, or acombination thereof, wherein the one or more olefins comprises ethylene,propylene, or a combination thereof, and wherein the olefin-based(co)polymer is an ethylene-containing (co)polymer, apropylene-containing (co)polymer, or a copolymer, mixture, or blendthereof

The invention will now be more particularly described with reference tothe following Examples and the accompanying drawings.

EXAMPLES

The analysis techniques described below were among those used incharacterizing various samples from the Examples.

ICP-OES

Elemental analysis has been done using ICP-OES (Inductively CoupledPlasma-Optical Emission Spectrometry). Samples were dissolved in amixture of acids and diluted in deionized water. The instrument(Simultaneous VISTA-MPX from Varian) was calibrated using commercialavailable standards (typically at least 3 standards and a blank). Thepower used was about 1.2 kW, plasma flow about 13.5 L/min, and nebulizerpressure about 200 kPa for all lines. Results are expressed in wt % orppm by weight (wppm), and the values are recalculated to Si/Al₂ molarratios.

XRD

Either of two X-ray diffractometers was used: a STOE Stadi-P Combi

Transmission XRD and a Scintag X2 Reflection XRD with optional samplerotation. Cu-K_(α) radiation was used. Typically, a step size of 0.2° 2Θand a measurement time of about 1 hour were used.

SEM

A JEOL JSM-6340F Field-Emission-Gun scanning electron microscope (SEM)was used, operating at about 2 kV and about 12 μA. Prior to measurement,samples were dispersed in ethanol, subjected to ultrasonic treatment forabout 5 to about 30 minutes, deposited on SEM sample holders, and driedat room temperature and pressure (about 20-25° C. and about 101 kPa). Ifan average particle size was determined based on the SEM micrographs,typically the measurement was performed on at least 30 crystals. In caseof the near cubic crystals, the average was based on the sizes of one ofthe edges of each crystal.

PSA

Particle size analysis was performed using a Mastersizer APA2000 fromMalvern Instruments Limited, equipped with a 4 mW laser beam, based onlaser scattering by randomly moving particles in a liquid medium. Thesamples to be measured were dispersed in water under continuousultrasonic treatment to ensure proper dispersion. The pump speed appliedwas 2000 RPM, and the stirrer speed was 800 RPM. The parameters used inthe operation procedure were: Refractive Index=1.544, Absorption=0.1.The results were calculated using the “general purpose-enhancedsensitivity” model. The results were expressed as d₅₀, meaning that 50vol % of the particles were smaller than the value. The average of atleast 2 measurements, with a delay of at least about 10 seconds, wasreported.

Comparative Example A1

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:1.5 DMCHA:40 H₂O, as well as 100 wt ppm (wppm) seeds,was prepared according to the following procedure. A solution ofphosphoric acid was prepared by combining phosphoric acid [Acros, 85%]and water. To this solution was added the appropriate amount of CondeaPural SB [Sasol, 74.2 wt % Al₂O₃], and the slurry was stirred for about10 minutes at about 10° C. To this mixture was added the appropriateamount of Ludox AS40 [ammonium stabilized silica sol containing 40 wt %SiO₂, from Grace NV] and the slurry was stirred for about another 10minutes at about 10° C. Then the appropriate amount ofdimethylcyclohexylamine [DMCHA, 99%, from Purum Fluka] was added. Thismixture was stirred for about 10 minutes before the seeds (SAPO-34seeds) were added. The final mixture was transferred to an autoclavewhich was stirred at approximately room temperature (about 20-25° C.)for about 2 hours, followed by heating, while stirring, to about 170° C.with a heat-up rate of about 40° C./hr. After about 72 hours thistemperature, the autoclave was cooled to approximately room temperature,and the solids were washed with demineralized water and dried at about120° C. The yield was determined by weighing the dried solids anddividing this weight by the weight of the initial synthesis mixture. Theso-calculated yield was about 12.5 wt %. The phase purity of the samplewas determined by X-ray diffraction to contain CHA framework, by virtueof exhibiting the peaks listed in Table 1 above, but also contained asignificant amount of peaks indicating AFI framework. The XRD pattern isshown in FIG. 1. An SEM micrograph was recorded (FIG. 2), and thecrystal size was approximated to be about 10 μm.

Comparative Example A2

A synthesis mixture having a molar composition of about 0.15 SiO₂:0.75P₂O₅:Al₂O₃:1.5 DMCHA:40 H₂O, as well as 100 wt ppm seeds, was preparedaccording to the following procedure. A solution of phosphoric acid wasprepared by combining phosphoric acid [Acros, 85%] and water. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,74.2 wt % Al₂O₃], and the slurry was stirred for about 10 minutes atabout 10° C. To this mixture was added the appropriate amount of LudoxAS40 [ammonium stabilized silica sol containing 40 wt % SiO₂, from GraceNV] and the slurry was stirred for about another 10 minutes at about 10°C. Then the appropriate amount of dimethylcyclohexylamine [DMCHA, 99%,from Purum Fluka] was added. This mixture was stirred for about 10minutes before the seeds (SAPO-34 seeds) were added. The final mixturewas transferred to an autoclave which was stirred at approximately roomtemperature for about 2 hours, followed by heating, while stirring, toabout 170° C. with a heat-up rate of about 40° C./hr. After about 72hours this temperature, the autoclave was cooled to approximately roomtemperature, and the solids were washed with demineralized water anddried at about 120° C. The yield was determined by weighing the driedsolids and dividing this weight by the weight of the initial synthesismixture. The so-calculated yield was about 14.9 wt %. The phase purityof the sample was determined by X-ray diffraction and was characterizedsubstantially by the d-spacings shown in Table 1 above. The XRD patternis shown in FIG. 3. An SEM micrograph was recorded (FIG. 4), and thecrystal size was approximated to be about 10 μm or smaller.

Example 1

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:1.5 DMCHA:40 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.About 25% of this phosphoric acid solution was removed and in its placea corresponding molar amount of triethylphosphate [TEP, 99.8+%, fromAldrich] was added. To this solution was added the appropriate amount ofCondea Pural SB [Sasol, 74.2 wt % Al₂O₃], and the slurry was stirred forabout 10 minutes at about 10° C. To this mixture was added theappropriate amount of Ludox AS40 [ammonium stabilized silica solcontaining 40 wt % SiO₂, from Grace NV] and the slurry was stirred forabout another 10 minutes at about 10° C. Then the appropriate amount ofdimethylcyclohexylamine [DMCHA, 99%, from Purum Fluka] was added. Thismixture was stirred for about 10 minutes before the seeds (SAPO-34seeds) were added. The final mixture was transferred to an autoclavewhich was stirred at approximately room temperature for about 2 hours,followed by heating, while stirring, to about 170° C. with a heat-uprate of about 40° C./hr. After about 72 hours this temperature, theautoclave was cooled to approximately room temperature, and the solidswere washed with demineralized water and dried at about 120° C. Theyield was determined by weighing the dried solids and dividing thisweight by the weight of the initial synthesis mixture. The so-calculatedyield was about 15.5 wt %. The phase purity of the sample was determinedby X-ray diffraction and was characterized substantially by thed-spacings shown in Table 1 above. The XRD pattern is shown in FIG. 5.An SEM micrograph was recorded (FIG. 6), and the crystal size wasdetermined to be about 5 μm or smaller.

Example 2

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:1.5 DMCHA:35 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.About 25 mol % of this phosphoric acid solution was removed. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,74.2 wt % Al₂O₃], and the slurry was stirred for about 10 minutes atabout 10° C. To this mixture was added the appropriate amount of LudoxAS40 [40 wt % SiO₂, from Grace NV] and the slurry was stirred for aboutanother 10 minutes at about 10° C. Then the appropriate amount ofdimethylcyclohexylamine [DMCHA, 99%, from Purum Fluka] was added. Tothis mixture was added triethylphosphate [TEP, 99.8+%, from Aldrich] ina molar amount corresponding to the removed phosphoric acid. Thismixture was stirred for about 10 minutes before the seeds (SAPO-34seeds) were added. The final mixture was transferred to an autoclavewhich was stirred at approximately room temperature for about 2 hours,followed by heating, while stirring, to about 170° C. with a heat-uprate of about 40° C./hr. After about 72 hours this temperature, theautoclave was cooled to approximately room temperature, and the solidswere washed with demineralized water and dried at about 120° C. Theyield was determined by weighing the dried solids and dividing thisweight by the weight of the initial synthesis mixture. The so-calculatedyield was about 13.8 wt %. The phase purity of the sample was determinedby X-ray diffraction and was characterized substantially by thed-spacings shown in Table 1 above. The XRD pattern is shown in FIG. 7.An SEM micrograph was recorded (FIG. 8), and the crystal size wasdetermined to be about 5 μm or smaller.

Example 3

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:1.5 DMCHA:40 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.About 25 mol % of this phosphoric acid solution was removed. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,74.2 wt % Al₂O₃], and the slurry was stirred for about 10 minutes atabout 10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TEOS, 98%, from Aldrich] and the slurry wasstirred for about another 10 minutes at about 10° C. Then theappropriate amount of dimethylcyclohexylamine [DMCHA, 99%, from PurumFluka] was added. To this mixture was added triethylphosphate [TEP,99.8+%, from Aldrich] in a molar amount corresponding to the removedphosphoric acid. This mixture was stirred for about 10 minutes beforethe seeds (SAPO-34 seeds) were added. The final mixture was transferredto an autoclave which was stirred at approximately room temperature forabout 2 hours, followed by heating, while stirring, to about 170° C.with a heat-up rate of about 40° C./hr.

After about 72 hours this temperature, the autoclave was cooled toapproximately room temperature, and the solids were washed withdemineralized water and dried at about 120° C. The phase purity of thesample was determined by X-ray diffraction and was characterizedsubstantially by the d-spacings shown in Table 1 above. An SEMmicrograph was recorded (FIG. 9), and the crystal size was determined tobe smaller than about 1 μm.

Example 4

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:1.5 DMCHA:35 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.About 25 mol % of this phosphoric acid solution was removed. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,74.2 wt % Al₂O₃], and the slurry was stirred for about 10 minutes atabout 10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TEOS, 98%, from Aldrich] and the slurry wasstirred for about another 10 minutes at about 10° C. Then theappropriate amount of dimethylcyclohexylamine [DMCHA, 99%, from PurumFluka] was added. To this mixture was added triethylphosphate [TEP,99.8+%, from Aldrich] in a molar amount corresponding to the removedphosphoric acid. This mixture was stirred for about 10 minutes beforethe seeds (SAPO-34 seeds) were added. The final mixture was transferredto an autoclave which was stirred at approximately room temperature forabout 2 hours, followed by heating, while stirring, to about 170° C.with a heat-up rate of about 40° C./hr. After about 72 hours thistemperature, the autoclave was cooled to approximately room temperature,and the solids were washed with demineralized water and dried at about120° C. The phase purity of the sample was determined by X-raydiffraction and was characterized substantially by the d-spacings shownin Table 1 above. An SEM micrograph was recorded (FIG. 10), and thecrystals appear to be relatively homogeneous in size and smaller thanabout 1 μm.

Comparative Example B1

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.To this solution was added the appropriate amount of Condea Pural SB[Sasol, 75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour atabout 10° C. To this mixture was added the appropriate amount of LudoxAS40 [ammonium stabilized silica sol containing 40 wt % SiO₂, from GraceNV]. Then the appropriate amount of dimethylcyclohexylamine [DMCHA, 99%,from Purum Fluka] was added. This mixture was stirred for about 10minutes before the seeds (SAPO-34 seeds) were added. The final mixturewas transferred to an autoclave which was heated, while stirring, toabout 170° C. with a heat-up rate of about 20° C./hr. After about 24hours this temperature, the autoclave was cooled to approximately roomtemperature, and the solids were washed with demineralized water anddried at about 120° C. The yield was determined by weighing the driedsolids and dividing this weight by the weight of the initial synthesismixture. The so-calculated yield was about 17.2 wt %. The phase purityof the sample was determined by X-ray diffraction and was characterizedsubstantially by the d-spacings shown in Table 1 above. An SEMmicrograph was recorded (FIG. 11), and the crystal size was determined,on average, to be approximately 2.5 μm.

Example 5

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.To this solution was added the appropriate amount of Condea Pural SB[Sasol, 75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour atabout 10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TEOS, 98%, from Aldrich]. Then the appropriateamount of dimethylcyclohexylamine [DMCHA, 99%, from Purum Fluka] wasadded. This mixture was stirred for about 10 minutes before the seeds(SAPO-34 seeds) were added. The final mixture was transferred to anautoclave which was heated, while stirring, to about 170° C. with aheat-up rate of about 20° C./hr. After about 24 hours this temperature,the autoclave was cooled to approximately room temperature, and thesolids were washed with demineralized water and dried at about 120° C.The yield was determined by weighing the dried solids and dividing thisweight by the weight of the initial synthesis mixture. The so-calculatedyield was about 10.5 wt %. The phase purity of the sample was determinedby X-ray diffraction and was characterized substantially by thed-spacings shown in Table 1 above. An SEM micrograph was recorded (FIG.12), and the crystal size was determined, on average, to be about 0.4 μmor smaller.

Example 6

A synthesis mixture having a molar composition of about 0.11SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 400 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.To this solution was added the appropriate amount of Condea Pural SB[Sasol, 75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour atabout 10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TEOS, 98%, from Aldrich]. This mixture was thenaged at about 10° C. while stirring for about another one hour. Then theappropriate amount of dimethylcyclohexylamine [DMCHA, 99%, from PurumFluka] was added. This mixture was stirred for about 10 minutes beforethe seeds (SAPO-34 seeds) were added. The final mixture was transferredto an autoclave which was heated, while stirring, to about 160° C. witha heat-up rate of about 40° C./hr. After about 144 hours thistemperature, the autoclave was cooled to approximately room temperature,and the solids were washed with demineralized water and dried at about120° C. The yield was determined by weighing the dried solids anddividing this weight by the weight of the initial synthesis mixture. Theso-calculated yield was about 6.9 wt%. The phase purity of the samplewas determined by X-ray diffraction and was characterized substantiallyby the d-spacings shown in Table 1 above. An SEM micrograph was recorded(FIG. 13), and the crystal size was determined, on average, to be about0.3 μm or smaller.

Examples 7-13

A series of samples was made according to the same procedure as Example6, but only changing the Si/Al₂ ratio of the synthesis mixture. Allproducts resulted in materials characterized substantially by thed-spacings shown in Table 1 above, with an average crystal size of about0.4 μm. The yield results are summarized in Table 2.

TABLE 2 Yield of products made using TEOS according to Examples 6-13with a heat-up rate of about 40° C./hr and various Si/Al₂ ratios in themixture. Example Si/Al₂ Yield % 6 0.11 6.9 7 0.12 8.0 8 0.13 8.2 9 0.149.2 10 0.15 9.8 11 0.16 10.3 12 0.17 10.6 13 0.18 10.1

Example 14

A synthesis mixture having a molar composition of about 0.11 SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 400 wt ppm seeds, was preparedaccording to the following procedure. A solution of phosphoric acid wasprepared by combining phosphoric acid [Acros, 85%] and water. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour at about10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TMOS, 99%, from Fluka]. This mixture was thenaged at about 10° C. while stirring for about another one hour. Then theappropriate amount of dimethylcyclohexylamine [DMCHA, 99%, from PurumFluka] was added. This mixture was stirred for about 10 minutes beforethe seeds (SAPO-34 seeds) were added. The final mixture was transferredto an autoclave which was heated, while stirring, to about 160° C. witha heat-up rate of about 40° C./hr. After about 144 hours thistemperature, the autoclave was cooled to approximately room temperature,and the solids were washed with demineralized water and dried at about120° C. The yield was determined by weighing the dried solids anddividing this weight by the weight of the initial synthesis mixture. Theso-calculated yield was about 8.6 wt %. The phase purity of the samplewas determined by X-ray diffraction and was characterized substantiallyby the d-spacings shown in Table 1 above. An SEM micrograph was recorded(FIG. 14), and the average crystal size was determined to be about 0.3μm or smaller.

Examples 15-21

A series of samples was made according to the same procedure as Example14, but only changing the Si/Al₂ ratio of the synthesis mixture. Allproducts resulted in materials characterized substantially by thed-spacings shown in Table 1 above, with an average crystal size of about0.3 μm. The yield results are summarized in Table 2.

TABLE 3 Yield of products made using TMOS according to Examples 14-21with a heat-up rate of about 40° C./hr and various Si/Al₂ ratios in themixture. Example Si/Al₂ Yield % 14 0.11 8.6 15 0.12 9.0 16 0.13 9.1 170.14 10.0 18 0.15 10.6 19 0.16 11.3 20 0.17 11.9 21 0.18 12.5

Example 22

A synthesis mixture having a molar composition of about 0.15 SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 400 wt ppm seeds, was preparedaccording to the following procedure. A solution of phosphoric acid wasprepared by combining phosphoric acid [Acros, 85%] and water. To thissolution was added the appropriate amount of Condea Pural SB [Sasol,75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour at about10° C. To this mixture was added the appropriate amount oftetraethylorthosilicate [TEOS, 98%, from Aldrich]. This mixture was thenaged at about 10° C. while stirring for about another one hour. Then theappropriate amount of dimethylcyclohexylamine [DMCHA, 99%, from PurumFluka] was added. This mixture was stirred for about 10 minutes beforethe seeds (SAPO-34 seeds) were added. The final mixture was transferredto an autoclave which was heated, while stirring, to about 170° C. witha heat-up rate of about 40° C./hr. After about 24 hours thistemperature, the autoclave was cooled to approximately room temperature,and the solids were washed with demineralized water and dried at about120° C. The yield was determined by weighing the dried solids anddividing this weight by the weight of the initial synthesis mixture. Theso-calculated yield was about 11.8 wt %. SEM micrographs were recorded,and the crystal size was determined, on average, to be about 0.5 μm orsmaller. The Si/Al₂ ratio in the recovered product was determined to beabout 0.23. The product sieve of Example 22 was pelletized and calcinedat about 600° C. for about 4 hours in air, and was then tested for itsmethanol-to-olefins (MTO) conversion performance under the followingconditions: reaction temperature of about 500° C.; WHSV of about 100 gMeOH/g sieve/hr; and total pressure of about 25 psig (about 273 kPag).The average prime olefin selectivity (POS) was determined to be about77.8 wt %.

Comparative Example C1

A synthesis mixture having a molar composition of about 0.15SiO₂:P₂O₅:Al₂O₃:2 DMCHA:40 H₂O, as well as 100 wt ppm seeds, wasprepared according to the following procedure. A solution of phosphoricacid was prepared by combining phosphoric acid [Acros, 85%] and water.To this solution was added the appropriate amount of Condea Pural SB[Sasol, 75.6 wt % Al₂O₃], and the slurry was stirred for about 1 hour atabout 10° C. To this mixture was added the appropriate amount of LudoxAS40 [ammonium stabilized silica sol containing 40 wt % SiO₂, from GraceNV]. After about 10 minutes, the appropriate amount ofdimethylcyclohexylamine [DMCHA, 99%, from Purum Fluka] was added. Thismixture was stirred for about 10 minutes before the seeds (SAPO-34seeds) were added. The final mixture was transferred to an autoclavewhich was heated, while stirring, to about 170° C. with a heat-up rateof about 20° C./hr. After about 48 hours this temperature, the autoclavewas cooled to approximately room temperature, and the solids were washedwith demineralized water and dried at about 120° C. The yield wasdetermined by weighing the dried solids and dividing this weight by theweight of the initial synthesis mixture. The so-calculated yield wasabout 16.5 wt %. SEM micrographs was recorded, and the crystal size wastypically about 2 μm or larger. The Si/Al₂ ratio in the recoveredproduct was determined to be about 0.15. The product sieve ofComparative Example C1 was pelletized and calcined at about 600° C. forabout 4 hours in air, and was then tested for its methanol-to-olefins(MTO) conversion performance under the following conditions: reactiontemperature of about 500° C.; WHSV of about 100 g MeOH/g sieve/hr; andtotal pressure of about 25 psig (about 273 kPag). The average primeolefin selectivity (POS) was determined to be about 76.5 wt %.

As can be seen from the above Examples and Comparative Examples, organicsilicon sources (e.g., alkoxy-functional silicates) demonstrate adistinct advantage over inorganic silicon sources (e.g., colloidalsilica) in both crystal size and POS (for methanol-to-olefinsreactions), though the sieve formation yields are not as high. Further,among organic silicon sources, TMOS advantageously shows slightly highersieve formation yields with relatively similar (or slightly smaller)crystal sizes. A graphical comparison of the yield vs. Si/Al₂ ratio insynthesis mixture, taken from Tables 2-3, is presented in FIG. 5.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For this reason, then, reference shouldbe made solely to the appended claims for purposes of determining thetrue scope of the present invention.

1.-16. (canceled)
 17. A method of forming an olefin-based polymerproduct comprising: (a) preparing a silicoaluminophosphate molecularsieve comprising; (i) combining a source of phosphorus and a source ofaluminum with a liquid mixture medium to form a primary mixture, whereinsaid source of silicon comprises an organosilicate and said source ofphosphorus comprises an organophosphate; (ii) aging the primary mixturefor an aging time and under aging in conditions sufficient to allowhomogenization of the primary mixture, physico-chemical interactionbetween the source of phosphorus and the source of aluminum, or both;(iii) adding a source of silicon, N,N-dimethylcyclohexylamine organictemplate, and optionally additional liquid mixture medium, to the agedprimary mixture to form a synthesis mixture; and (iv) inducingcrystallization of a silicoaluminophosphate molecular sieve, whichexhibits 90% or greater CHA framework type character, from saidsynthesis mixture at a crystallization temperature, wherein thecrystallized silicoaluminophosphate molecular sieve has a crystal sizedistribution such that its average crystal size is not greater than 5μm; (b) formulating said silicoaluminophosphate molecular sieve, alongwith a binder and optionally a matrix material, into asilicoaluminophosphate molecular sieve catalyst composition comprisingfrom at least 10% to about 50% molecular sieve; (c) contacting saidcatalyst composition with a hydrocarbon feed under conditions sufficientto convert said hydrocarbon feed into a product comprising predominantlyone or more olefins; (d) polymerizing at least one of the one or moreolefins, optionally with one or more other comonomers and optionally inthe presence of a polymerization catalyst, under conditions sufficientto form an olefin-based (co)polymer.
 18. The method of claim 17, whereinthe hydrocarbon feed is an oxygenate-containing feed comprisingmethanol, dimethylether, or a combination thereof, wherein the one ormore olefins comprises ethylene, propylene, or a combination thereof,and wherein the olefin-based (co)polymer is an ethylene-containing(co)polymer, a propylene-containing (co)polymer, or a copolymer,mixture, or blend thereof.
 19. The method of claim 17, wherein thecrystallized silicoaluminophosphate molecular sieve exhibits a Si/Al₂ratio not more than 0.10 greater than the Si/Al₂ ratio of the synthesismixture.
 20. The method of claim 17, wherein said crystallizationtemperature is between 150° C. and 200° C.
 21. The method of claim 17,wherein the crystallized silicoaluminophosphate molecular sieve has acrystal size distribution such that the average crystal size is lessthan 2.0 μm.
 22. The method of claim 17, wherein the crystallizedsilicoaluminophosphate molecular sieve has a crystal size distributionsuch that the average crystal size is less than 1.2 μm.
 23. The methodof claim 17, wherein the inducing step is done while stirring.
 24. Themethod of claim 17, wherein, within step (iii), said source of siliconis combined with said primary mixture prior to adding said at least oneorganic template.
 25. The method of claim 24, wherein said primarymixture and said source of silicon are combined to form a secondarymixture for a time and under conditions sufficient to allowhomogenization of the secondary mixture, physico-chemical interactionbetween said source of silicon and said primary mixture, or both, afterwhich said at least one organic template is combined therewith.
 26. Themethod of claim 17, wherein the synthesis mixture and the crystallizedsilicoaluminophosphate molecular sieve both exhibit a Si/Al₂ ratio lessthan 0.33.
 27. The method of claim 17, wherein one or more of thefollowing are satisfied: the source of aluminum comprises alumina; thesource of phosphorus comprises phosphoric acid and an organophosphatecomprising a trialkylphosphate; the organosilicate comprises atetraalkylorthosilicate; and the at least one organic template comprisesN,N-dimethylcyclohexylamine.
 28. The method of claim 17, wherein theorganosilicate comprises tetramethylorthosilicate,tetraethylorthosilicate, or a combination thereof.
 29. The method ofclaim 17, wherein step (iv) was accomplished using seeds having aframework type of CHA, AEI, AFX, LEV, an intergrowth thereof, or acombination thereof.